This invention relates generally to imaging systems, and more particularly, to diagnostic imaging systems.
In imaging systems, small data errors may cause artifacts, such as smudges, spots, bands, center spots, rings, and streaks, to appear in the reconstructed image. The data errors may be a result of malfunctioning of the components of the imaging systems or may be caused by the patient, such as due to a patient's motion. Failure to account for these errors during image reconstruction may result in a loss in image quality. These errors also may cause a large discrepancy between the scanned object and the reconstructed image. Hence, such artifacts and data errors should be diagnosed and repaired prior to scanning an object to improve image quality and results.
Various methods are known for diagnosing an imaging system. One most commonly used method is manual diagnosis of the imaging system. The service engineer diagnoses the problem based on his past experience. However, this method may not work to identify the cause of certain types of artifacts that can arise from multiple causes. For example, a band artifact may be caused by a problem in a detector or due to the presence of particles in the x-ray beam path. To distinguish between the two causes, images can be acquired in both the cold state and hot state of an X-ray tube. For example, an image is acquired initially with the X-ray tube in a cold state. Then the X-ray tube is heated for approximately an hour or more, and another image is acquired. If the two images or scan data show any difference, the problem can be diagnosed as a particle in the beam path. However, these methods rely on the expertise of the operator and are often time consuming.